How do you crop an image in iOS - iphone

Question

I have a photo app where you can add stickers in one section. When you're finished I want to save the image. Here is the code that I have to do that.
if(UIGraphicsBeginImageContextWithOptions != NULL)
{
UIGraphicsBeginImageContextWithOptions(self.view.frame.size, YES, 2.5);
} else {
UIGraphicsBeginImageContext(self.view.frame.size);
}
CGContextRef contextNew=UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:contextNew];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Now the image that gets saved is the full screen of the image, which is fine, but now I need to crop the image and I don't know how. You can see the image at the link below:
http://dl.dropbox.com/u/19130454/Photo%202012-04-09%201%2036%2018%20PM.png
I need to crop:
91px from the left and right
220px from the bottom
Any help would be greatly appreciated. If I haven't explained things clearly, please let me know and I'll do my best to re-explain.

Answer 1

How about something like this
CGRect clippedRect = CGRectMake(self.view.frame.origin.x+91, self.view.frame.origin.y, self.view.frame.size.width-91*2, self.view.frame.size.height-220);
CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], clippedRect);
UIImage *newImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

Answer 2

Following code may help you.
You should get the correct cropFrame fist by below method
-(CGRect)cropRectForFrame:(CGRect)frame
{
// NSAssert(self.contentMode == UIViewContentModeScaleAspectFit, #"content mode must be aspect fit");
CGFloat widthScale = imageview.superview.bounds.size.width / imageview.image.size.width;
CGFloat heightScale = imageview.superview.bounds.size.height / imageview.image.size.height;
float x, y, w, h, offset;
if (widthScale<heightScale) {
offset = (imageview.superview.bounds.size.height - (imageview.image.size.height*widthScale))/2;
x = frame.origin.x / widthScale;
y = (frame.origin.y-offset) / widthScale;
w = frame.size.width / widthScale;
h = frame.size.height / widthScale;
} else {
offset = (imageview.superview.bounds.size.width - (imageview.image.size.width*heightScale))/2;
x = (frame.origin.x-offset) / heightScale;
y = frame.origin.y / heightScale;
w = frame.size.width / heightScale;
h = frame.size.height / heightScale;
}
return CGRectMake(x, y, w, h);
}
Then you need to call this method to get cropped image
- (UIImage *)imageByCropping:(UIImage *)image toRect:(CGRect)rect
{
// you need to update scaling factor value if deice is not retina display
UIGraphicsBeginImageContextWithOptions(rect.size,
/* your view opaque */ NO,
/* scaling factor */ 2.0);
// stick to methods on UIImage so that orientation etc. are automatically
// dealt with for us
[image drawAtPoint:CGPointMake(-rect.origin.x, -rect.origin.y)];
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}

Answer 3

- (UIImage*)imageByCropping:(CGRect)rect
{
//create a context to do our clipping in
UIGraphicsBeginImageContext(rect.size);
CGContextRef currentContext = UIGraphicsGetCurrentContext();
//create a rect with the size we want to crop the image to
//the X and Y here are zero so we start at the beginning of our
//newly created context
CGRect clippedRect = CGRectMake(0, 0, rect.size.width, rect.size.height);
CGContextClipToRect( currentContext, clippedRect);
//create a rect equivalent to the full size of the image
//offset the rect by the X and Y we want to start the crop
//from in order to cut off anything before them
CGRect drawRect = CGRectMake(rect.origin.x * -1,
rect.origin.y * -1,
self.size.width,
self.size.height);
//draw the image to our clipped context using our offset rect
// CGContextDrawImage(currentContext, drawRect, self.CGImage);
[self drawInRect:drawRect]; // This will fix getting inverted image from context.
//pull the image from our cropped context
UIImage *cropped = UIGraphicsGetImageFromCurrentImageContext();
//pop the context to get back to the default
UIGraphicsEndImageContext();
//Note: this is autoreleased
return cropped;
}

Answer 4

Refer the below link for crop image
https://github.com/myang-git/iOS-Image-Crop-View
** How to Use **
Very easy! It is created to be a drop-in component, so no static library, no extra dependencies. Just copy ImageCropView.h and ImageCropView.m to your project, and implement ImageCropViewControllerDelegate protocol.
Use it like UIImagePicker:
- (void)cropImage:(UIImage *)image{
ImageCropViewController *controller = [[ImageCropViewController alloc] initWithImage:image];
controller.delegate = self;
[[self navigationController] pushViewController:controller animated:YES];
}
- (void)ImageCropViewController:(ImageCropViewController *)controller didFinishCroppingImage:(UIImage *)croppedImage{
image = croppedImage;
imageView.image = croppedImage;
[[self navigationController] popViewControllerAnimated:YES];
}
- (void)ImageCropViewControllerDidCancel:(ImageCropViewController *)controller{
imageView.image = image;
[[self navigationController] popViewControllerAnimated:YES];
}